Continuity tester



United States Patent CONTINUITY TESTER Harold Gordon Curd, Chicago, 111.

Application August 28, 1953, Serial No. 377,076

3 Claims. (Cl. 324-53) This invention relates to a continuity tester and more particularly to means for adapting a flashlight for use as a continuity tester.

A major feature of this invention is the provision of novel, small, cheaply manufactured plug means with which a flashlight may be adapted for use as a continuity tester, to test the electrical continuity of a circuit.

Another feature is that the continuity tester comprises a flashlight including a housing, battery means, light bulb means and an electrical circuit connecting the light bulb means with the battery and means are provided for making a testing connection to the electrical circuit through the housing. A furtherfeature is that the side wall of the housing has an opening therein and plug means are insertable through the opening in the side wall to break the electrical circuit of the flashlight and testing means are connected to the plug means through which the electrical circuit may be completed. Still another feature is that the electrical circuit of the flashlight includes a member which overlies and contacts another portion of the circuit and the testing plug comprising two conductive elements insulated from each other and adapted to be inserted between the circuit member and the other portion of the circuit breaking the electrical contact.

A further feature is that only a portion of the plug is inserted inside the housing and the insulated portion is substantially at right angles to the remainder of the plug, facilitating the insertion and withdrawal of the plug. Yet another feature is that a portion of the wall of the housing adjacent the opening therethrough is cut away to facilitate insertion of the plug. And a further feature is that means are provided on the plug for preventing undesired movement thereof after it has been inserted in the opening in the wall of the housing of the flashlight.

Further features and advantages will be readily apparent from the following specification and from the drawings in which:

Figure 1 is a perspective view of a flashlight with a preferred embodiment of the continuity testing apparatus of this invention in place;

Figure 2 is a sectional view taken as indicated by the line 22 of Figure 1;

Figure 3 is an elevational view of the plug assembly with a portion broken away;

Figure 4 is a bottom plan view of the plug of Figure 3;

Figure 5 is an elevational view taken from the left of Figure 3; and

Figure 6 is an elevational view taken from the right of Figure 3.

As shown in Figure l, a flashlight 10 is provided with an opening in the side wall thereof through which a plug assembly 11 may be inserted. As will appear presently, the insertion of the plug assembly breaks the electrical circuit of the flashlight and accordingly the flashlight will not light when the plug is in place. The plug assembly 11 is provided with a pair of test leads 12 and 13 which have suitable connecting means at the ends thereof as the alligator clips 14 and 15. If the alligator clips are connected together, either directly or through a continuous electrical circuit, the electrical circuit of the flashlight will again be completed, lighting the flashlight and thus providing an indication of continuity.

Referring now to Figure 2, the housing of the flashlight 10 includes an elongated tubular body or side wall portion 10a, which is preferably of a non-conducting material, and end caps 10b and 100. Lens cap 10b holds in place the reflector and bulb unit 16 and the lens 17 while base cap 10c closes the other end of the housing and acting through battery bias spring 18 secures batteries 19v in position in the housing. An operative circuit for the energization of light bulb 20 by batteries 19 includes the battery bias spring 18, a metal ring 21 around the interior surface of the housing at the base of the batteries and conductive strip 22 secured to the ring 21 and extending longitudinally a short distance along the interior wall of the housing. Switch means are provided for selectively energizing the light bulb 20, including an elongated strip 23 of rather springy conductive material movably mounted on the interior surface of the flashlight housing 10 and a thumb operating member 23a. When the springy member 23 is in the forward position, the end 23b opposite the free end 23a contacts the outer surface of the reflector 16a which is of a conductive material completing the electrical circuit. The thumb operated member 23a extends through the wall of the housing 10a and provides a means for manually changing the position of the member controlling the circuit of the flashlight. One terminal 20a of the light bulb contacts the reflector 16a while the other terminal 20b is connected through a spring contactor 25 to the positive terminal 19a of the battery means.

The test plug assembly 11 may best be seen in Figures 3-6 and comprises a pair of conductive plate 26 and 27 separated by an insulating spacer member 28. The members of the plug may be secured together by suitable means such as the threaded bolt 29 which is insulated from the conductive members 26 and 27 by insulating strips 30 and 31. One end, 11a, of the plug assembly is formed at substantially right angles to the remainder of the plug. Test leads 12 and 13 are attached to the conductive plates 26 and 27 respectively at the end of the plug opposite the end 11a.

An opening 10a is provided in the side wall 10a of the flashlight housing transverse to the longitudinal axis of the housing and adjacent the free end 23a of the elongated springy member 23.

The end 11a of the plug assembly 11 is insertable through the opening 10d in the side wall of the flashlight housing 10a as shown in Figure 2, separating the free end of the elongated springy member 23a from the strip or other portion of the circuit 22 and breaking the energizing circuit for the bulb 20 of the flashlight. When the plug is properly inserted, the conductive strip 26 is in contact with the portion of the circuit 22 while conductive strip 27 contacts the elongated member 23. As the conductive strips 26 and 27 of the plug 11 are electrically insulated from each other, bulb 20 may be energized only through the test leads 12 and 13. Thus when the test leads are connected directly together or are connected to a continuous electrical circuit the flashlight will light indicating the continuity.

The right angled configuration of the test plug 11 is desirable to facilitate the insertion and removal of the plug in the opening 10d. The outer wall of the housing adjacent the opening 10d and remote from the free end 23a of the springy member is cut away as shown at 10e to permit the plug to be inserted in the opening. The insulating members 30 and 31 on the plug 11 abut against the outer wall of the housing 10a when the plug is in place preventing any undesired movement thereof.

Two continuity testers may be used by two operators when matching circuits in positions remote from each other without the necessity of providing means for the operators to communicate with each other as both flashlights will light when the circuit is completed. Of course, when the test plug 11 is not connected with the flashlight, the flashlight will operate normally, thus serving a dual purpose.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. A continuity tester of the character described, comprising: a flashlight including a tubular housing having a wall, battery means, a light bulb and electrical circuit Patented Mar. 1, 1955 means operably connecting said light bulb with said battery means, said circuit means including a longitudinally extending member having a free end overlying and contacting another portion of the circuit, said housing having an opening in. the wall thereof transverse to the longitudinal axis of the housing and adjacent the free end of said member; a plug comprising two conductive elements insulated from each other and adapted tobe inserted through said opening and between said member and said other portion of the circuit, breaking said circuit, the outer wall of said housing on. the side of said opening remote from the free end of said member being cut away to permit said plug to be inserted and removed readily; and a pair of test leads, one connected to each of said conductive elements whereby said electrical circuit may he completed through said test leads.

2. A continuity tester of the character described, comprising: a flashlight including a tubular housing, battery means, a light bulb and electrical circuit means operably connecting said light bulb with said battery means, said circuit means including an elongated, longitudinally extending springy member overlying and contacting another portion of the circuit, said housing having an open ing therein transverse to the longitudinal axis of the housing; a plug comprising two conductive elements insulated from each other and adapted to be inserted through said opening and between said elongated membet and said other portion of the circuit, breaking the circuit, only a portion of said plug being inserted inside the housing and the inserted portion being substantially at right angles with respect to the remainder of the plug, and the outer wall of said housing adjacent said opening and remote from the free end of said springy member being cut away to permit said plug to be inserted and removed readily; raisedmeans on the external portion of said plug adapted to abut against the wall of said housing preventing undesired movement of said plug; and a pair of test leads, one connected to each of said conductive elements whereby said electrical circuit may be completed through said test leads.

3. A continuity tester of the character described, comprising: a flashlight including a housing having a side wall, battery means, a light bulb and electrical circuit means operably connecting said light bulb with said battery means, said circuit means including a member overlying and contacting. another portion of the circuit, said housing having an opening in the side wall thereof, adjacent said member; a plug comprising two conductive elements insulated from each other and having a portion adapted to be inserted through said opening and between said member and said other portion of the electrical circuit, breaking said electrical circuit, the inserted portion being substantially at right angles to the remainder of the plug; and a pair of test leads, one connected to each of said conductive elements whereby said electrical circuit may be completed through said test leads.

References Cited in the file of this patent UNITED STATES PATENTS 1,508,990 Schmidt Sept. 16, 1924 1,679,786 Roberts Aug. 7, 1928 1,950,486 Frank Mar. 13, 1934 1,980,721 Jenkins Nov. 13, 1934 2,231,660 Carlotti et al. Feb. 11, 1941 2,302,248 Olson Nov. 17, 1942 

